U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  7

                                                                                
Station ID: 8530095                         PUBLICATION DATE:  06/16/2004
Name:       ALPINE, HUDSON RIVER                              
            NJ
NOAA Chart: 12343                           Latitude:   40° 56.7' N (  40.94500)
USGS Quad:  YONKERS                         Longitude:  73° 55.1' W ( -73.91830)


To reach the tidal bench marks, proceed along the Palisades Interstate Parkway
to Alpine, then continue to the west side of the Hudson River to Palisades State
Park.  The bench marks are located in the vicinity of the piers and buildings of
the Palisades Interstate Park Commission.  The tide gage and staff were at the
Alpine Boat Basin.


                         T I D A L   B E N C H   M A R K S
                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  7

                                                                                
Station ID: 8530095                         PUBLICATION DATE:  06/16/2004
Name:       ALPINE, HUDSON RIVER                              
            NJ
NOAA Chart: 12343                           Latitude:   40° 56.7' N (  40.94500)
USGS Quad:  YONKERS                         Longitude:  73° 55.1' W ( -73.91830)


                         T I D A L   B E N C H   M A R K S


                 PRIMARY BENCH MARK STAMPING:  NO 1 1932
                         DESIGNATION:          TIDAL 1 STA 1

MONUMENTATION:           Tidal Station disk                    VM#:         2420
AGENCY:                  US Coast & Geodetic Survey
                         (USC&GS)                                 IDB PID#:  KU1630
SETTING CLASSIFICATION:  Rock cliff                            OPUS PID:        
LATITUDE:   40° 56.8' N (  40.94670)          LONGITUDE:  73° 55.1' W ( -73.91830)


The primary bench mark is a disk set vertically into the east face of a rock
cliff of the Palisades, 0.2 km (0.1 mi) north of the Alpine Yonkers ferry
landing, 16.31 m (53.5 ft) SW of the SW corner of a small wood bridge, 9.75 m
(32.0 ft) north of the NW corner of the Cornwallis Headquarters, 3 m (10 ft)
west of the centerline of a gravel road on the west side of the house, and 1 m
(2 ft) above road level.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  7

                                                                                
Station ID: 8530095                         PUBLICATION DATE:  06/16/2004
Name:       ALPINE, HUDSON RIVER                              
            NJ
NOAA Chart: 12343                           Latitude:   40° 56.7' N (  40.94500)
USGS Quad:  YONKERS                         Longitude:  73° 55.1' W ( -73.91830)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  NO 2 1932
                         DESIGNATION:          TIDAL 2 STA 1

MONUMENTATION:           Tidal Station disk                    VM#:         2421
AGENCY:                  US Coast & Geodetic Survey
                         (USC&GS)                                 IDB PID#:  KU1631
SETTING CLASSIFICATION:  Rock face of bluff                    OPUS PID:        
LATITUDE:   40° 56.8' N (  40.94670)          LONGITUDE:  73° 55.1' W ( -73.91830)


The bench mark is a disk set vertically into the rock face of the Palisades, 0.2
km (0.1 mi) north of the Alpine Yonkers ferry landing, 35.66 m (117.0 ft) north
of bench mark NO 1 1932, 16.76 m (55.0 ft) SW of the SW corner of a refreshment
pavilion (north stand), 8.53 m (28.0 ft) west of the centerline of the
employee's road, 5.33 m (17.5 ft) SW of the SW corner of the old Alpine Trail
Monument, and 0.91 m (3.0 ft) above ground.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  7

                                                                                
Station ID: 8530095                         PUBLICATION DATE:  06/16/2004
Name:       ALPINE, HUDSON RIVER                              
            NJ
NOAA Chart: 12343                           Latitude:   40° 56.7' N (  40.94500)
USGS Quad:  YONKERS                         Longitude:  73° 55.1' W ( -73.91830)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  NO 3 1932
                         DESIGNATION:          TIDAL 3 STA 1

MONUMENTATION:           Tidal Station disk                    VM#:         2422
AGENCY:                  US Coast & Geodetic Survey
                         (USC&GS)                                 IDB PID#:  KU1632
SETTING CLASSIFICATION:  Retaining wall                        OPUS PID:        
LATITUDE:   40° 56.8' N (  40.94670)          LONGITUDE:  73° 55.1' W ( -73.91830)


The bench mark is a disk set on top of and at the south end of a rock and
concrete retaining wall, 0.2 km (0.1 mi) north of the Alpine Yonkers ferry
landing, 32.31 m (106.0 ft) north of bench mark NO 2 1932, 30.48 m (100.0 ft) NW
of a small pavilion, and 3 m (10 ft) east of the centerline of a trail.



                         BENCH MARK STAMPING:  0095 A 1975
                         DESIGNATION:          853 0095 A TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         2423
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Brick foundation                      OPUS PID:        
LATITUDE:   40° 56.7' N (  40.94500)          LONGITUDE:  73° 55.1' W ( -73.91830)


The bench mark is a disk set vertically into the east face of a concrete and
brick building, at the Alpine Boat Basin, east of exit 2 of the Palisades State
Park, 35.94 m (117.9 ft) west of the chain link fence on the wood bulkhead at
the Hudson River, 34.99 m (114.8 ft) north of the NE corner of a concrete garage
building, 26.49 m (86.9 ft) from the SE corner, 4.66 m (15.3 ft) from the NE
corner of the building, and 1 m (2 ft) above the pavement.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  7

                                                                                
Station ID: 8530095                         PUBLICATION DATE:  06/16/2004
Name:       ALPINE, HUDSON RIVER                              
            NJ
NOAA Chart: 12343                           Latitude:   40° 56.7' N (  40.94500)
USGS Quad:  YONKERS                         Longitude:  73° 55.1' W ( -73.91830)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  0095 B 1975
                         DESIGNATION:          853 0095 B TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         2424
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Rock cliff                            OPUS PID:        
LATITUDE:   40° 56.7' N (  40.94500)          LONGITUDE:  73° 55.1' W ( -73.91830)


The bench mark is a disk set vertically into the east face of the rock cliff of
the Palisades, 0.2 km (0.1 mi) north of the Alpine Yonkers ferry landing, 45.26
m (148.5 ft) north of bench mark NO 3 1932, 26.64 m (87.4 ft) NW of a 3-foot
high stone wall, 18.59 m (61.0 ft) north of the NE corner of a large stone
pavilion building, 12.68 m (41.6 ft) SW of the SW corner of the first of several
stone picnic tables along the shore, and 1 m (2 ft) above ground level.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  6 of  7

                                                                                
Station ID: 8530095                         PUBLICATION DATE:  06/16/2004
Name:       ALPINE, HUDSON RIVER                              
            NJ
NOAA Chart: 12343                           Latitude:   40° 56.7' N (  40.94500)
USGS Quad:  YONKERS                         Longitude:  73° 55.1' W ( -73.91830)


                            T I D A L   D A T U M S 


Tidal datums at ALPINE, HUDSON RIVER based on:

     LENGTH OF SERIES:      9 MONTHS
     TIME PERIOD:           March 1976 - November 1976
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8518750 THE BATTERY, NEW YORK HARBOR


Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:

     MEAN HIGHER HIGH WATER                     MHHW   =  1.278
     MEAN HIGH WATER                            MHW    =  1.201
     MEAN SEA LEVEL                             MSL    =  0.658
     North American Vertical Datum              NAVD88 =  0.636
     MEAN TIDE LEVEL                            MTL    =  0.629
     MEAN LOW WATER                             MLW    =  0.058
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     NO 1 1932                                   2.755    1.554
     NO 2 1932                                   3.229    2.028
     NO 3 1932                                   7.588    6.388
     0095 A 1975                                 2.917    1.716
     0095 B 1975                                 3.088    1.887


                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  7 of  7

                                                                                
Station ID: 8530095                         PUBLICATION DATE:  06/16/2004
Name:       ALPINE, HUDSON RIVER                              
            NJ
NOAA Chart: 12343                           Latitude:   40° 56.7' N (  40.94500)
USGS Quad:  YONKERS                         Longitude:  73° 55.1' W ( -73.91830)


                             D E F I N I T I O N S


Mean Sea Level (MSL) is a tidal datum determined over a 19-year National Tidal
Datum Epoch.  It pertains to local mean sea level and should not be confused
with the fixed datums of North American Vertical Datum of 1988 (NAVD88).

NAVD88 is a fixed datum derived from a simultaneous, least squares, minimum
constraint adjustment of Canadian/Mexican/United States leveling observations.
Local mean sea level observed at Father Point/Rimouski, Canada was held fixed as
the single initial constraint.  NAVD88 replaces NGVD29 as the national
standard geodetic reference for heights.  Bench mark elevations relative to
NAVD88 are available from NGS through the World Wide Web at 
National Geodetic Survey.

NGVD29 is a fixed datum adopted as a national standard geodetic reference for
heights but is now considered superseded.  NGVD29 is sometimes referred to as
Sea Level Datum of 1929 or as Mean Sea Level on some early issues of Geological
Survey Topographic Quads.  NGVD29 was originally derived from a general
adjustment of the first-order leveling networks of the U.S. and Canada after
holding mean sea level observed at 26 long term tide stations as fixed.
Numerous local and wide-spread adjustments have been made since establishment in
1929.  Bench mark elevations relative to NGVD29 are available from the National
Geodetic Survey (NGS) data base via the World Wide Web at 
National Geodetic Survey.

NAVD88 and NGVD29 are fixed geodetic datums whose elevation relationships to
local MSL and other tidal datums may not be consistent from one location to
another.

The Vertical Mark Number (VM#) and PID# shown on the bench mark sheet are unique
identifiers for bench marks in the tidal and geodetic databases, respectively.
Each bench mark in either database has a single, unique VM# and/or PID# assigned.
Where both VM# and PID# are indicated, both tidal and geodetic elevations are
available for the bench mark listed. The NGS's Integrated Data Base (IDB PID)
provides geodetic datum based on traditionally leveled and bluebooked ties to
the National Spatial Reference System(NSRS) https://www.ngs.noaa.gov/datasheets/.
The NGS Online Positioning User Service (OPUS PID) provides geodetic datum based
on GPS position & tie it to the NSRS https://www.ngs.noaa.gov/OPUS/.

The NAVD88 elevation is shown on the Elevations of Tidal Datums Table Referred
to MLLW only when two or more of the bench marks listed have NAVD88 elevations.
The NAVD88 elevation relationship shown in the table is derived from an average
of several bench mark elevations relative to tide station datum.  As a result of
this averaging, NAVD88 bench mark elevations computed indirectly from the tidal
datums elevation table may differ slightly from NAVD88 elevations listed for
each bench mark in the NGS database.